1. Field of the Invention
The present invention relates to a foldable stretcher for use in transporting non-ambulatory persons, and in particular including an improved articulating joint.
2. Description of Related Art
Stretcher frames for use in transporting non-ambulatory persons are well-known, and are widely used in hospitals, nursing homes and the like, as well as by ambulance and emergency personnel in transporting injured or ill persons from remote locations to a hospital by means of ground or air transport. In such cases, the emergency vehicle must be equipped with stretchers adapted for such use since, in some cases, a stretcher may be used to carry a person some distance to reach an emergency vehicle, or for transporting a person by means of more than one type of vehicle en route to a hospital.
Stretchers may therefore have frames which are foldable or collapsible so that the stretcher may be stored in a relatively small space, and readily carried to a remote location if required. It is also desirable that the frame of a foldable stretcher include a minimum number of components, be light in weight and be easy to operate. Efforts have been made to design stretchers, and stretcher frames in particular, to meet some or all of these requirements.
U.S. Pat. No. 2,400,155 to Letschert discloses a combination stretcher and invalid's reclining chair which has a pair of longitudinal rails connected by a pair of cross members. A pair of inner frames support the stretcher material, and are pivotably mounted on the cross members for lowering a foot rest section and raising a torso support section of the stretcher for converting the stretcher into a chair. The longitudinal rails each include a pair of handle sections attached to the frame rail by means of a sliding pivot joint for folding the handles inwardly toward the center of the rail. The sliding pivot joint, including the end portion of the handle section, is normally disposed entirely within the hollow rail, which "sleeves" the joint and locks it in its extended position. To fold the handles, the handle section end and pivoting joint is pulled axially partially out of the frame rail, and the handle folded over to lay against the frame rail.
U.S. Pat. Nos. 3,655,297 to Bolen et al and 4,611,945 to Diego each disclose articulating joints for use in coupling tubular members, and which may be used in constructing a stretcher frame. U.S. Pat. No. '297 to Bolen et al discloses a coupling for a paddle or the like having a first end rigidly attached within the end of a first tube, and having a second end slidingly and rotatably retained within the second tube by a nut fixed within the second tube which engages the raised threads at each end of a rod extending from the coupling end. The joint is fixed in its rigid configuration by sliding the pivoting portions 16, 18, and 24 of the joint into the second tube 10, and the joint in place there by engaging threads 32 in nut 26. To collapse the joint, tube 12 is rotated relative to tube 10 to disengage threads 32 from nut 26, tubes 10 and 12 are pulled apart to expose the pivoting parts of the joint, and tubes 10 and 12 are folded parallel. The '297 joint is not suitable for use where tubes 10 and 12 are rotationally or axially fixed with respect to one another as is often the case with a stretcher frame.
U.S. Pat. No. '945 to Diego discloses an articulating joint which, when in its rigid position, is housed within tubular members 10 and 12, and which is held in its locked position by biased pins 24 a and b engaged in holes 28 and 30. Pins 24 a and b rotationally fix the joint with respect to each tubular member. To flex the joint, the pins are pulled out from their holes, the tubes are pulled apart, and the tubular members pivoted. The '945 joint is not suitable for use where tubes 10 and 12 are axially fixed with respect to one another, as is often the case with a stretcher frame.
U.S. Pat. No. 1,906,218 to Patchell discloses an articulating joint comprising a link pivotally connecting the mitered ends of abutting shafts, and a sliding sleeve for locking the joint in its rigid position.
Each of the above disclosed joints is further limited in that each provides only a single available direction of folding for the frame relative to the one or both of the tubular members.
A need remains therefore for a foldable stretcher frame incorporating an articulating joint which allows the tubular members to be locked against upward or downward flexing, or folded either upwardly or downwardly relative to the joint; and which can be readily operated to flexing or locking positions while the tubular members remain rotationally and axially fixed relative to each other.